St. Cedd was the eldest of four brothers, born into a noble Northumbrian family at the beginning of the 7th century. With his siblings, Cynebil, Caelin & (St.) Chad, he entered the school at Lindisfarne Priory at an early age and learnt the ways of the Irish monks under Bishop Aidan. They were eventually sent to Ireland for further study and all four subsequently became priests.

Bishop Finan of Lindisfarne subsequently sent Cedd out to evangelise the people of Essex, who were sorely in need of some spiritual guidance. He baptised many of the locals and built several churches - and is particularly noted for the foundation of monasteries at Bradwell-on-Sea and East Tilbury.

Having been ordained as Bishop of Essex by Bishop Finan Cedd re-instated St. Paul's in London as the main seat of his diocese. He ordained priests and deacons to assist him in his work and gathered together a large flock of servants of Christ in his two monastic foundations.

Bishop Cedd always remained fond of his Northern homeland, however, and made regular visits there. On one such occasion in AD 658, Cedd was approached by King Aethelwald of Deira. Finding Cedd to be a good and wise man, he pressed upon him to accept a parcel of land at Lastingham in Yorkshire on which to build a monastery. Cedd eventually agreed, but would not lay the foundation stones until the place had first been cleansed through prayer and fasting. Cedd was the first Abbot of Lastingham and remained so while still administering to his flock in Essex.

In AD 664 Cedd was at Lastingham while a great plague was raging through the area. Both he and his brother, Cynebil, fell sick and, after placing Lastingham in the charge of their youngest brother, Chad, they died. Cedd was first buried in the open air and his funeral was attended by some thirty monks from Bradwell who, sadly, also contracted the plague and died. Eventually, a little stone church was built at the Lastingham, in honour the Virgin Mary, and Cedd's body was interred there, to the right of the altar. The latter remains intact in the Norman crypt that was later built on the site, though St. Cedd's bones were removed around the same time to the cathedral founded by his brother, Chad, at Lichfield.